261042805 has 8 divisors (see below), whose sum is σ = 329738400. Its totient is φ = 197842896.

The previous prime is 261042797. The next prime is 261042839. The reversal of 261042805 is 508240162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 261042805 - 2³ = 261042797 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1373815 + ... + 1374004.

It is an arithmetic number, because the mean of its divisors is an integer number (41217300).

Almost surely, 2^261042805 is an apocalyptic number.

It is an amenable number.

261042805 is a deficient number, since it is larger than the sum of its proper divisors (68695595).

261042805 is a wasteful number, since it uses less digits than its factorization.

261042805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2747843.

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 261042805 is about 16156.8191485824. The cubic root of 261042805 is about 639.1025874447.

Adding to 261042805 its reverse (508240162), we get a palindrome (769282967).

The spelling of 261042805 in words is "two hundred sixty-one million, forty-two thousand, eight hundred five".